Hints and Kinks

I will start with one on transferring rib patterns to balsa wood. If you copy the rib sections only onto a separate piece of paper on a copy machine, you can then lay the copy pattern face down on the balsa and iron the print onto the wood. Since copy machines use heat to set the ink on the paper, heating it in that way will melt and transfer the ink just like you were printing it onto the wood in the first place.

OK, your turn. What do you have to offer?

I do like your idea, though.

Another one: To raise or lower a tank in a full fuse compartment, I use clear plastic bubble sheets used for packing. Use the kind with the smaller bubbles. I cut the sheet out in the same size as the tank, like 4" by 1.5", or whatever.

A section of a Pringles potato chip can makes a good start for a cowl. Use the rolled lip for the front.

You can find little teeny tiny instrument panels in Flying magazine.

Cheapskate Special: Punch out and save the eyelets from those little Perfect parts packages.

Here is a summary of some things I have stolen from this forum.

1. Make everthing (fuel tank, leadouts, wingtip weight, gear, controls) as adjustable and removable for modification as possible. (Wise words from one of this forum's Black Belts)

2.Use no CYA where you might ever sand. CYA weeps out to a hard rock that is unsandable (is that a word?).

3. Freely throw kit parts away and upgrade / reinforce.

4. Buy tools. Buy good tools. As a teen, I "drilled" motor mount holes by heating 1/8" music wire and making repeated attempts at making the hole. I will never scrimp on tools again! The difference between an expert builder and the others is often in the quality / choice of tools.

5. Design or steal alignment jigs / ideas from anyone you can. Straight is good. Crooked is bad. The brass tubing extensions as landing gear alignment guides is an example of "stealing" an idea.

Go to the fancy-schmancy subdivision in your neighborhood where they are building overpriced homes, and go to their scrap wood junk pile. Grab what you need, like a flat launching pad, a building board, etc. Notice that I'm not, repeat NOT suggesting that you five finger discount any stuff that the builders are going to use. (Up here, in the Detroit 'burbs, the builders mostly are are Cosa Nostra, so you end up being really, really bashful around the building site. Like, I can lose my fingers in Nelsons the honest way).

Cut a piece of wood like a 30-60-90 triangle. Make it thick enough so that it will stand on its own. It's relly good for aligning your wing and stab at 90 degrees and straight with the fuse when you sight from the nose down the plane. You just slide the hypoteneuse in and out to you get it right.

I did some tests, and your plan works well. I would call it brilliant, but then you would get a swelled head!

Because of my business, I hate paper as a media for any EXACT image transfer images (it is to prone to anamorphic distortion with heat and humidity because of grain). I used transparency material (that stuff you make copies on of your presentation when the CEO is visiting). With the iron on method, the transperancies provided a sharper transfer image than paper -- less fuzzy around the edges.

Using the overhead material as templates (cutting the ribs out with scissors, then following around the edge with a razor blade) DID NOT work. The media is too flimsy even with crutches and tape help.

With either media, I got a slight size change from the original, and both about the same. The error is around .020 over 9" (thickness of ribs is OK, length is a fuzz short), and the copy is the smaller of the two. We can live with that, right? I mean is a judge going to tell you you are not OT legal for .020? It may be I have a funky copier and you will do better.

That would make for interesting conversation if you were lucky enough to crash in front of a large crowd, and the spectators helped you pick up the pieces.

When you do these templates, start with a half pattern of the rib section. Draw a centerline on your template material, lay the half pattern in place, draw around it. Then flip the pattern over to draw the other half. Now the top and bottom curves should be identical. Old work workers trick.

I very much like the 1/64" plywood, too. I built a flapped profile stunter many years ago that had the plywood on the fuse, wings sheeted with 1/32 balsa and silkspan. Also had a 3/4" wide spruce beam running the length of the entire fuselage-in the center. Would have made a good baseball bat. Survived everything except a run-in with a 4 strand wire fence....

I think the half rib and flip approach is obsolete with cadcam plans. In the 60s, I used to build most everything that way. The flip variation caused by the builder's vision limitations can be as much as .010 (.005 with a 7X magnifier)and I have data collected under ideal conditions, not in the building room. With hand drawn plans, the plan error is probably greater than .005. With cadcam plans, the plan error is zero, so I would prefer not to flip in today's world.

This is obviously more important in tapered wings than in straight wings where you can assure symmetry with a sanding block. Yeah, you can assure symmetry with a sanding block on tapered wings also, but I am not going to write 4 pages saying why I think that is a bad plan.

Larry, some copiers are intentionally set up to make the copy "slightly" smaller. Zerox is notorious for that. We had a Zerox machine at our church and we were copying forms that would be used to type permanent records into. (Records that could be placed into a book). The original form was spaced perfectly for the typewriter. We made a copy of it, pasted some stuff on it, and made a copy of that. It had shrunk just enough that the typewriter spacing was now off. The next time the Zerox repairman was out (about once a week or so) I asked him about it. He said it was purposely set up so it would make a copy slightly smaller so you would be sure of getting all of your copy on. I asked if he could adjust it for exact size and he said, "Yes, but I am not allowed to do that." I said, "We bought this machine! We are the ones who allow you to do it." After about another half hour of persuasion while he was on the clock and undoubtedly charged us for it, he did adjust the machine accordingly. So, if your machine is set to reduce, as you say, it should probably be a simple adjustment that could be made the next time your friendly repairman is out. Or, try a 101% copy and see what that does.

Although the error is only on the order of 1/4 of a percent, I wouldn't be surprised if 101% isn't a better choice. I will do a test. I didn't really check to see if the distortion was anamorphic. If it is, I can't change the direction of the ribs, as they are longer than the 8 1/2 media width. I have to run them in the length of the rib as the "through the machine" direction.

It is irritating that some bozo makes a product and makes mathematical round offs and adjustments for the user, and is arrogant about why that is "good for" the end user.

Thanks to both of you, I have a better picture of how to attack the problem. I'll let you know the results.

Tom M

--Use the silver oxide sandpaper for sanding dope. It doesn't load up.

--Make your own tools to hollow out blocks. Take varous sizes of brass tubing (I use 1/4", 3/8" and 1/2"). Cut about a 1/2" off the end of the tube and split it. Straighten out the sides and solder it at an angle on the end of the tube. You can use an x-acto knife to sharpen both sides of the loop to push or pull though balsa. Beats every other tool to hollow balsa I've tried.

--You can get stainless steel "T" 4/40 bolts from a nut and bolt shop. They are killer for pushrod ends.

That's all I can think of for the moment.

Randy, what the heck is a "T" bolt? Sounds like a good name for a fighter or a glowplug! Steve

I got mine from a place called Hi-Strength Bolt.

G. Man

Bill Sawyer sells them in three sizes.

You could also use the above method to line up the 2 engines of a twin-engine stunter, just squint along the wing to make sure the "props" are parallel.
I did this with real props on my last twin, your idea sounds much better